Selectively engageable intermittent motion mechanism



June 11, 1957 c, sElDLER 2,795,150

SELECTIVELY ENGAGEABLE INTERMITTENT MOTION MECHANISM Filed June 17, 1954 INVENTOR CLI FFORD D. SEIDLER Bf WM ATTORNEY United States Patent 0 SELECTIVELY ENGAGEABLE INTERMITTENT MOTION MECHANISM Clifford D. Seidler, Glenview, lll., assignor to Teletype Corporation, Chicago, Ill., a corporation of Delaware Application June 17, 1954, Serial No. 437,520 11 Claims. (Cl. 74-436) This invention relates to selectively engageable intermittent motion mechanisms and more particularly to mechanisms for moving a driving element into and out of position to drive a Geneva wheel.

Many machines found in the printing telegraph art utilize intermittent drive mechanisms in the performance of some part of their overall operation. For example, in telegraph recorders it is necessary to intermittently advance new areas of a recording medium into position to be acted upon by the recording elements. In general, the well known pawl and ratchet mechanism, in some form or other, has been employed to attain the desire-d intermittent motion. However, with the development of high speed recording devices it is necessary to avoid the impartation of shock to any of the recording medium advancing mechanism. Prior art pawl and ratchet de vices are susceptible to the impartation of shock when operating at high speeds hence reducing the accuracy of operation and also utilimately resulting in a shortened life expectancy. An intermittent motion device which possesses desirable shock free characteristics is the Geneva wheel mechanism but this device continually operates; viz. each cyclic operation of the drive element results in an incremental rotation in the Geneva wheel. A further requirement necessary for adaptability of a mechanism in telegraph machines for advancing recording medium resides in the ability to be selectively operated to impart one or a predetermined number of incremental advances to the driven element and then be capable of being rendered ineffective for an indeterminate period of time.

An object of the invention resides in a simple intermittent motion transmission mechanism having selectively operable facilities for interrupting the transmission of any motion.

In concord with the first object, it is a further object of the invention to provide instrumentalities for preventing the operation of the interrupting means during periods in which the mechanism is actually transmitting motion from one part to another.

Another object of the invention which is commensurate with the first two objects resides in means for reconditioning the mechanism for further transmission of intermittent motion without any danger of clashing of the elements.

A further and more finite feature of the invention resides in a Geneva wheel mechanism having either electro-mechanical or mechanical means for selectively moving a constantly rotating drive element into and out of position to effectuate a transmission of intermittent motion to the Geneva wheel.

With these and other objects in view the present invention contemplates a Geneva wheel adapted to be intermittently driven by a constantly rotating driving element. This driving element is mounted on a constantly rotating shaft in such a manner that rotation of the shaft is imparted to the driving element but the driving element ice is also susceptible of being axially moved along the shaft. Selectively operable means controlled at the discretion of an attendant are provided to slide a driving element along the shaft to withdraw said element from position to drive the Geneva wheel. Blocking means are provided to pre clude the withdrawal of the driving element when said element is in the act of imparting movement to the Geneva Wheel. The blocking means are automatically rendered ineffective upon the subsequent withdrawal of the driving element from the Geneva wheel. The blocking clement further functions to prevent the repositionment of the driving element when said element would clash with the Geneva wheel.

Other objects and advantages of the present invention will be apparent from the following detailed description when considered in conjunction with the accompanying drawing wherein:

Fig. l is a perspective view showing a mechanical means for selectively engaging and disengaging a Geneva wheel mechanism embodying the principal features of the invention; and

Fig. 2 is a perspective view of an alternative embodiment of the invention showing electromechanical control means for selectively moving the drive means into and out of position to effectuate operation of 21 Geneva wheel.

Referring to Fig. 1, there is illustrated a constantly rotating shaft 10 mounted in suitable bearings and adapted to be driven by a constantly operating motor (not shown). Keyed or splined to the shaft 10 is a disc 11 adapted to rotate with the shaft, but being also capable of being axially moved along the shaft. The disc 11 has a cavity formed therein to provide a concave surface 12 which runs partially through the width of the disc 11. Secured to the side of the disc 11 and to a hub 13 of said disc is an operating arm 14 extending radially from the shaft 10 to intersect the are described by the surface 12 at its midpoint. Attached to the arm 14 is a roller 16 adapted to ride within one of a set of slots 17 formed in a Geneva wheel 18 when said roller has been rotated through one complete revolution. Upon each successive rotation of the roller 16 about shaft 10, the roller 16 successively rides within the next successive grooves 17. The Geneva wheel 18, illustrated in Fig. 1, has four slots 17 formed therein and four concave surfaces 19 but it is to be understood that more could be provided to secure smaller increments of movement upon each rotation of the roller 16.

As the roller 16 is rotated it enters a slot 17 in the Geneva wheel 18 and rotates the same a distance equal to the distance between the centers of the outer extremity of a pair of adjacent slots 17. When the roller 16 leaves a slot 17, the Geneva wheel 18 is held stationary by the periphery of the disc 11 engaging one of said concave surfaces 19. Obviously the provision of the cavity in the disc 11 permits the roller 16 to impart rotation to the Geneva wheel without any interference.

Also secured to or formed integral with the disc 11 is the hub portion 13 which is also adapted to rotate with the shaft 10 and be axially moved along said shaft. The hub 13 is provided with a circumferential groove 21 into which is positioned one arm 22 of an L-shaped lever 23 pivotally mounted at 24. Hub 13 is also provided with a second groove section 26 interrupted by the provision of an island 27. The island 27 describes an arc which when measured in degrees is equal to the are described by the cavity formed in the disc 11. It will be noted that the arc of the island is in lateral register with respect to the arc of cavity formed in disc 11. Positioned within the groove 26 is a stop element 28 rigidly secured to some portion of the frame for supporting the mechanism.

With the elements in the positions shown in Fig. i, the depression of the lever 23 causes a counterclockwise move- .3 ment to be imparted to the arm 22 which in turn acts on the lef hand surface of the groove 21, to axially slide the hub 13 and disc 11 along the shaft 10. Movement of the disc 11 also results in a movement being imparted to the arm 14 and roller 16, thereby withdrawing roller 16 from position to effectuate a transmission of motion to the Geneva wheel 18. The disc 11 is axially moved a sufficient amount so that the uninterrupted peripheral surface thereof is positioned to continually engage a concave surface of the Geneva wheel 18 and consequently the Geneva wheel is locked from any further movement.

In the situation where the roller 16 is operating within one of the slots 17, it is desired to preclude an interruption of the transmission of motion to the Geneva wheel. With the roller 16 positioned within a groove 17, the island 27 is advanced into position to be in lateral register with the stop element 28 so that any attempt to actuate the lever 23 is ineffective to move the hub 13 and the disc 11 along the rotating shaft 10. When the roller 16 is withdrawn from the slot 17, then the island is no longer positioned in lateral register with the stop element 28 and the depression of the lever 23 results in the movement of the disc 11 along the shaft to cause the withdrawal of the roller 16 from position to drive the Geneva wheel 18.

Assuming that the roller 16 has been withdrawn from its driving position and is positioned in lateral register with the Geneva wheel 18 and further that it is desired to resume the transmission of intermittent movement, then the movement of the lever 23 in a clockwise direction is precluded because the island is again moved into lateral register with the stop element 28. Immediately after the island 27 is rotated past the stop element 28, the lever 23 is permitted to be moved in a clockwise direction to axially slide the hub and disc along the shaft 10 to reposition the roller 16 to again permit movement thereof within the slot 17 thereby driving the Geneva wheel 18.

Attention is directed to Fig. 2 wherein an alternative embodiment of the invention is shown employing electromechanical means for precluding disengagement of the roller 16 when in the process of transmitting driving power or the repositionment of the roller 16 when said roller is moved to the nondriving position and is in a lateral alignment with the Geneva wheel.

In this embodiment, the construction of the disc 11, roller 16, and Geneva wheel 18 is identical with the mechanism as shown in Fig. l, but in this instance the hub 13 is only provided with a single circumferential groove 31. Positioned within the groove 31 is an armature 32 adapted to be selectively controlled by a solenoid 33. The shaft 10 has securely mounted thereon a cam 34 adapted to cyclically close a movable contact 36 with :1 stationary contact 37 when the roller 16 is not operating in one of the slots 17 formed in the Geneva wheel 18. The cam 34 is provided with a recessed section so that the movable contact 36 is moved into engagement with a second stationary contact 38 when said low portion is presented to the movable contact 36. A compression spring 39 is provided to urge the movable contact 36 into engagement with the periphery of the cam 34.

With the elements in the positions shown in Fig. 2, the closure of a switch 41 completes a circuit from positive battery, through the movable contact 36, through the stationary contact 37, through the now closed manual switch 41, through the solenoid 33, to negative battery. Energization of the solenoid 33 draws up the armature 32 and the extremity thereof acts against the left-hand wall of the groove 31 to axially slide the hub 13 and disc 11 along the shaft 10. Axial movement of these elements along the shaft 10 results in a repositioning of the roller 16 so that motion cannot be imparted to the Geneva wheel 18. Obviously the opening of the manual switch 41 results in a deenergization of the solenoid 33 to allow a spring 42 to restore the armature 32 to the position shown in Fig. 2. Restoration of the armature 32 to the normal position returns the hub 13, disc 11, and roller 16 to the position wherein driving power is again intermittently transmitted to the Geneva wheel 18.

In the situation where the roller 16 is positioned in one of the slots 17, then the closure of the switch 41 is ineffective to energize the solenoid 33. This is true because the low portion of the cam 34 is presented to the movable contact arm 36 during the period in which the roller 16 is acting in one of the slots 17. The contact arm 36 is now in engagement with the stationary contact 38 and disengaged from the contact 37; consequently the energizing circuit to the solenoid 33 cannot be completed until such time as the high portion of the cam 34 again moves the movable contact arm 36 into engagement with the stationary contact 37. The length of the low portion of the cam 34 is such as to position the movable contact arm in engagement with the stationary contact 38 during the entire period in which the roller 16 is acting in one of the grooves 17.

Considering now the situation where the solenoid 33 is energized and the roller 16 is withdrawn from position to transmit driving power to the Geneva wheel 18, but is in lateral register with the Geneva wheel, and it is desired to resume the intermittent transmission of power. then the opening of the manual switch 41 is ineffective to de-energize the solenoid 33 because of a locking circuit established by the concurrent closure of a contact pair 43 by the armature 32 and the presentment of the low portion of the cam 34 to the movable contact arm 36. In this instance, the locking circuit may be traced from positive battery, through the movable contact arm 36, through the stationary contact 38, through the now closed contact pair 43, through the solenoid 33 to negative battery. As soon as the roller 16 is moved from lateral register with the Geneva wheel 18 then the high portion of the cam 34 is again presented to the movable contact arm 36 to withdraw said arm from the stationary contact 38 thereby interrupting the locking circuit to the solenoid 33. Inasmuch as the manual switch 41 has been previously opened, the solenoid is de-energized and the spring 42 is effective to pivot the armature 32 whereby the hub 13, disc 11, and roller 16 are axially moved along the shaft 10 to reposition the roller 16 in position to re-establish the intermittent driving relationship.

It is to be understood that the above-described arrangements of elements and construction of parts are simply illustrative of the application of the principles of the invention and many other modifications may be made without departing from the invention.

What is claimed is:

1. In a selectively engageable mechanism, a driven member, a rotating shaft, a drive member mounted for rotation with said shaft and axial movement along said shaft, said drive member adapted to impart intermittent motion to said driven member, means for interrupting the impartation of motion to the driven member, and means for engaging the interrupting means to preclude the operation of the interrupting means only when said drive means is imparting motion to said driven member.

2. In a selectively engageable mechanism, a Geneva wheel, a rotating shaft, a drive member mounted to rotate on the shaft and axially slide thereon, means for axially sliding the driving member into the out of position to drive the Geneva wheel, and means for engaging said axially sliding means to block axial movement of the drive member when said drive member is driving said Geneva wheel.

3. In a selectively engageable mechanism, a Geneva wheel, a driving member for imparting intermittent movement of said wheel, means for mounting said driving member for longitudinal movement, sliding means for longitudinally moving said member into and out of position to drive said Geneva wheel, and blocking means laterally positioned with respect to said sliding means for engaging said sliding means to block said longitudinal movement of said driving member when said member is in driving engagement with said wheel, said blocking means being also positioned to engage said sliding means to preclude the re-establishment of said intermittent driving relationship when said driving member is in lateral register with said Geneva wheel.

4. In an intermittent motion mechanism, a Geneva wheel, a driving element, means for rotating the driving element to impart intermittent rotation to the Geneva wheel, means for locking the Geneva wheel against rotations during periods in which the driving element is not imparting rotation to the Geneva wheel, means normally ineffective for locking the Geneva wheel during entire cycles of rotation of said driving element, and selectively operable means for rendering ineffective said driving element and rendering eifective said normally ineffective locking means.

5. In a selectively operable drive mechanism, a driven member, a rotating shaft, a drive member mounted on said shaft for rotation therewith and for axial movement therealong, said drive member adapted to impart movement to said driven member during a portion of each cycle of rotation, means for axially moving the drive member to preclude the impartation of any movement to the driven member, a fixed blocking element, and an element rotatable with said shaft to cooperate with said fixed blocking element to prevent axial movement of said drive element when said drive element is imparting movement to said driven member.

6. In an intermittent motion mechanism, a driven member, a drive element normally positioned to impart intermittent motion to said driven member, a manually operable lever for moving the drive element into a position to preclude further impartation of movement to the driven member, a fixed blocking element, a second blocking element movable with said drive element and co operable with said fixed locking element during periods in which the drive element is imparting movement to said driven member to prevent the operation of the manually operable lever.

7. In an intermittent motion mechanism, a driven member, driving means for imparting intermittent motion to said driven member, a normally de-energized solenoid controlled means for moving the driving means to preclude further impartation of said intermittent motion, means for energizing said solenoid controlled means, and cyclically operable means operated by said driving means for preventing the energization of said solenoid controlled means during impartation of said intermittent motion.

8. In an intermittent motion mechanism, a driven member, a rotating shaft, a drive member mounted for rotation with said shaft and axial movement along said shaft, said drive member normally positioned to impart intermittent motion to said driven member, a solenoid controlled means adapted to move said drive member from position to impart said intermittent motion, an

energizing circuit for said solenoid control means, a selectively operable switch in said control circuit, a contact biased to open position included in said control circuit, and a cam driven by said drive means for holding said contact closed during periods in which no intermittent motion is being imparted to said driven member.

9. In an intermittent motion mechanism, a driven member, a drive means normally positioned to impart intermittent motion to said driven member, a solenoid controlled means adapted to move said drive means from said motion imparting position, an energizing circuit for operating said solenoid control means, a selectively operable switch for conditioning said energizing circuit for operation, a first contaotor biased to open position in said energizing circuit, a cam driven by said drive means for closing said contactor to operate said conditioned circuit when no intermittent motion is being imparted to said driven member, a locking circuit including a pair of contacts for said solenoid control means, means actuated by the operation of said solenoid control means for operating a first of said pair of open contacts, and means operated by the cam for closing the second of said pair of normally open contacts when the cam is not closing said first mentioned contaetor.

10. In a selectively engageable mechanism, a driven member, a driving member for intermittently rotating the driven member through a predetermined number of radians, means for disrupting the transmission of motion to the driven member, a control member driven by said driving member and having an arcuate circumferential surface which subtends an angle equal to said predetermined number of radians, and means cooperable with said control member during movement of the drive member through said predetermined number of radians for precluding operation of the disrupting means.

11. In a selectively engageable mechanism, a Geneva wheel having a plurality of radially extending slots which are evenly spaced a predetermined number of radians apart, a driving member for imparting movement to said Geneva wheel through said predetermined number of radians, selectively operable means for moving said driving member to preclude the imparting of motion to the Geneva wheel, a control member driven by said driving member having an arcuate circumferential length which subtends an angle equal to said predetermined number of radians, :and means cooperating with said control member during movement of the driving member through said predetermined number of radians for precluding operation of said selectively operable means.

References Cited in the file of this patent UNITED STATES PATENTS 966,090 Hamacek Aug. 2, 1910 2,589,940 Hayek Mar. 18, 1952 FOREIGN PATENTS 903,991 France Oct. 23, 1945 

